In recent years, three-dimensional (3D) printing technologies, also referred as additive manufacturing (AM) technologies are rapidly developed and become increasingly popular. A fused deposition modeling (FDM) technology is commonly used in much equipment. In accordance with the operating principle of the AM technology, a three-axis transmission system or a single-axis transmission system and nozzles cooperate to extrude a plastic material or other build material in order to produce a three-dimensional object. The material is usually held by a ratchet and driven to the nozzle with the friction force. When a spray head is heated to a specific temperature, the material is melted so as to be extruded as a thread form from the small spray head, thereby filling up the slicer zone and formed layer by layer.
Since the method of inputting the material is implemented by holding and pushing the material with the ratchet, the unpredictable abnormal input issues are easy to occur (e.g. the material is knotted, the material wire is broken, the material is exhausted, the ratchet is skidded and the spray head is blocked). When the abnormal input issues occur during printing, the issues cannot be instantly known by most of the conventional 3D printers. It causes that the equipment is continuously operated, so a carbon accumulation with empty burning of the spray head is occurred and the ratchet is milled.
As shown in the application CN 203496156U, an error feeding detection device of a 3D printer is disclosed. Although the rotational speed of the coupling wheel can be monitored by the speed sensor disposed inside the coupling wheel, only the inputting status can be known in this manner. The issues that the material is knotted, the material wire is broken, the material is exhausted, the ratchet is skidded and the spray head is blocked cannot be instantly known in the first time. The common problems and drawbacks of the conventional 3D printers cannot be effectively solved.
Therefore, there is a need of provides an extrusion device of a three-dimensional printer and an optical detection mechanism thereof in order to overcome the above drawbacks.